For example, in a clutch, brake, automatic transmission, limited slip differential, hoist, synchronizer, torque converter, torque transmission system, or other friction type power transmission system or power absorption system etc., in general, one or more sets of co-actuating members are provided together with a friction material. One of the co-actuating members is driven or braked by the other.
Further, to transmit rotational drive force to a compressor for an air-conditioner which is mounted in an automobile, or to disconnect it, in the past, a magnetic clutch including a mechanism for transmission of rotational drive force through the friction surface of a friction material has been used (see Japanese Patent Publication Nos. H08-114241A and 2005-180474A).
Therein, it has been considered important to secure the fixing strength of the friction material to the apparatus to improve the operating performance and safety in an automobile in which the apparatus was mounted. Higher fixing strength has been demanded for fixing a friction material to a friction material-fixing portion of the apparatus. Note that, in this apparatus, in order to improve the corrosion resistance, cation electrodeposition coating etc., was usually used to coat, dry, and cure a paint containing a thermosetting resin etc., in a coating process, and thus the friction material-fixing portion was also coated.
In order to fix the friction material to the friction material-fixing portion, after the paint containing a thermosetting resin etc., being coated and cured in advance in this way, for improving the strength of fixing the friction material to the friction material-fixing portion, usually it was necessary to interpose an adhesive sheet or adhesive containing an adhesive ingredient to adhere them. Such an adhesive sheet or adhesive has been used to secure a predetermined adhesive strength. Therein, in order to interpose an adhesive layer, in addition to the preliminary layer formed by coating the paint containing a thermosetting resin etc., for the purpose of improving the corrosion resistance, complicated quality controls, such as suitably controlling qualities of three interfaces of the interface between the friction material-fixing portion and the layer of coating, the interface between the layer of coating and the adhesive layer, and the interface between the adhesive layer and friction material, are considered necessary.
As specific examples thereof, for example, Japanese Patent Publication No. 2004-044792A aims to provide an apparatus and method of attaching and joining a friction material to a clutch pulley, which enable automatic inspection of the coated state of a liquid phase adhesive which is coated in a friction material groove in the process of adhesion of a friction material at a clutch pulley, and thereby enable improvement of productivity and prevention of products with poorly adhered friction materials, and discloses a method of bonding a friction material to a clutch pulley, including a step of intermittently transferring a clutch pulley (P) by a transferring means, the clutch pulley having a friction material inserting groove (G) of a round shape wherein friction material (FM) is inserted into an end thereof; a step of injecting and coating a liquid phase adhesive by a dispenser unit having a nozzle capable of injecting the liquid phase adhesive (A) into the friction material inserting groove (G) of the clutch pulley (P); a coated state confirming step of sensing the coated condition of the liquid phase adhesive (A) coating the friction material inserting groove (G) of the clutch pulley (P) and generating warning sound if the coated condition of the liquid phase adhesive (A) is bad; a step of inserting the friction material (FM) into the friction material inserting groove (G) of the clutch pulley (P) coated with the liquid phase adhesive (A) by a friction material inserting means; and a step of induction-heating and hardening the liquid phase adhesive (A) by an induction heating means while compressing the friction material (FM) to bond the friction material to the friction material inserting groove (G). Therein, the friction surface of the magnetic clutch is provided with a groove for fitting the friction material over the entire circumference of the clutch pulley to adhere the friction material to that groove to transmit power.
Note that, while not explicitly shown in Japanese Patent Publication No. 2004-044792A, in such a clutch pulley, usually it was considered necessary to coat the surface of the clutch pulley in advance with a paint containing a thermosetting resin etc., then heat it to cure the resin and form a paint film so as to improve the corrosion resistance of the clutch pulley. Japanese Patent Publication No. H04-290618A describes electrodeposition coating of the clutch rotor as such a rust-proofing treatment.
FIG. 5 schematically shows, as an example of such a prior art, an adhered composite with a four-layer structure, obtained by coating and curing a paint containing a thermosetting resin etc., in advance at the surface of a rotor 2 having a groove part and through holes 5 at the bottom part of that in a magnetic clutch, i.e., a coating object, so as to form a paint film 3, then coating an adhesive 4 or attaching an adhesive sheet 4 for the purpose of adhering the surface of the paint film 3 in the groove part and a friction material 1, i.e., an adherend, adhering the two and thereby attaching the friction material 1 to the magnetic clutch rotor 2.
Further, FIG. 6 shows, as a reference example of a magnetic clutch in such a prior art, one provided with a rotor 8 having a friction surface of a friction material 7 which rotates upon transmission of rotational drive force, an armature 9 having a friction receiving surface which is arranged facing the friction surface of the rotor 8, electromagnetic coils 10, 10′ which are energized to generate magnetic force and pull the armature 9 to the rotor 8 side, and a hub 11 which transmits rotational drive force of the armature 9 to a compressor. Note that, a magnetic clutch 6 is provided for engaging and disengaging rotational drive force which is transmitted from a not shown engine of an automobile to a refrigerant compressor for an automobile air-conditioning system, so is comprised of a rotor 8 formed integrally with the pulley 12 which is driven to rotate by the engine, a hub 11 as a driven rotary member being provided with an armature 9 which faces the rotor 8 and can engage by friction, electromagnetic coils 10, 10′ which are energized to generate magnetic force, pull the armature 9 and thereby make this engage by friction with the rotor 8, etc. The pulley 12 has a not shown multi-ribbed V-belt wound around it, while the rotor 8 is supported to freely rotate through a bearing 14 at its inside circumference. The rotor 8 is comprised of a ring-shaped inside wall 15 which is positioned at the inside circumference side of the electromagnetic coil 10, a ring-shaped outside wall 16 which is positioned at the outside circumference side of the electromagnetic coil 10 and is formed integrally with the pulley 12, and a ring-shaped bottom wall 17 which can engage by friction with the armature 9. While ring shaped overall, the partial radial direction cross-section is U-shaped. The bottom wall 17 is provided with arc-shaped through holes 5, 5′ which perform the role of breaking the magnetic paths. The arc-shaped through holes 5, 5′ prevent the formation of magnetic paths directly between their inside walls 15 and the magnetic material part 19 and between the magnetic material part 19 and the outside walls 16, and are for making the magnetic flux repeatedly cut across and pass the frictionally engaged surfaces between the friction surface 20 of the rotor 8 and the friction surface 21 of the armature 9. In addition to the arc-shaped through holes 5 (corresponding to arc-shaped through hole 5 in FIG. 5), a ring-shaped groove is formed at the outer circumferential side of the friction surface of the bottom wall 17 (corresponding to rotor 2 in FIG. 5). In that groove, to raise the engagement force with the armature 9, a ring-shaped friction material 7 (corresponding to friction material 1 in FIG. 5) is fit as shown as FIG. 5, whereby the adhered composite with the four-layer structure is formed.
Note that, regarding the method of adhering parts when assembling a general product, Japanese Patent Publication No. H07-305035A discloses a method of adhering by a resin-based paint, comprising coating at least one part of two or more parts to be adhered with a resin-based paint which has adhesiveness, assembling the coated part to abut against another part, then baking it to adhere the abutting portions of the parts by the adhesive strength of the paint. However, with such a method of adhesion, depending on the obtained product, sometimes the adhesion strength is insufficient, so further improvement has been required.